Brake



July 24;*1934.

L. E. LA BRIE BRAKE `Filed sept. 6, 1928 f INVENToR.

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A TTORNEY Patented July 24, 1934 PATENT OFFICE BRAKE Ludger E. La Brie,South Bend, Ind., assignor to Bendix Brake Company, South Bend, Ind., a

corporation of Illinois Application September B. 1928, Serial No.304,126 21 Claims. (Cl. 188-78) This invention relates to brakes, and isillustrated as embodied in an internal expanding automobile brake of thetype having one part which anchors when the drum is turning in one Idirection and a different part which anchors when the drum is turning inthe other direction.

An important object of the invention is to improve the smoothness ofoperation of the brake, and to eliminate unbalanced forces and sudden lshifts of the anchorage, by an improved arrangement and construction ofthe parts. One important feature relates to arranging to have thebrake-applying forces thrust against the shoes or their equivalentsalong lines passing substantially through the brake anchors, so thatthere is no tendency to shift the shoes on the anchors, preferably byrounding the shoe ends on arcs having theircenters substantially in theaxes of the anchors.

Such rounded construction also makes possible the brake adjustment,through the expanding means at the lower part of the brake, without anyshifting of the shoes on their anchors. The original set of the brakeapplying lever is also maintained by virtue of this construction, whichconstruction is advantageously combined with a number of improvements inthe shoes and in the anchorage meansmore fully described below. y

I prefer to apply the brake by means such as a lever-type applyingdevice, embodying in itself substantial novelty, in such a manner thatthere is a greater thrust on the primary shoe (i. e. the one which isunanchored and which serves asa servoshoe when the car is movingforward) than on the normally-anchored or secondary shoe. Taken with thereturn spring connecting the shoes, this greater thrust on the primaryshoe yieldingly holds the' secondary shoe against its anchor until thebrake is applied to such an-extent that the drum friction takes control'of the anchorage, and either continues to hold the secondary shoeanchored if the car is moving forward or reverses the anchorage if thecar" is moving'backward. Thus there is no shifting of the anchorage atall in the ordinary case, with the car moving forward, while in theoccasional case when the car is moving backward the shifting takes placerelatively slowly and before the brake is fully applied, so that thereis no disagreeable shock or noise.

In connection with these novel features, I find it advantageous to usean improved arrangement of the auxiliary return spring, inclining it atsuch an angle as to urge the shoes bodily against their anchors,preferably, however, in such a manner as to act about the secondaryanchor pin as a fulcrum 'and through the floating shoe connection to ugethe other shoe toward a novel stop which determines the positions of theshoes when the brake is released.

Other features of the invention relate to novel means holding theadjustable floating shoe connection, to a new and very rigid mountingfor the brake anchors, and to other desirable details of constructionwhich will be apparent from the following description of theillustrative embodiment shown in the accompanying drawing, in which:

Figure 1 is a vertical section through the brake, just inside the headof the brake drum, and showing the brake shoes in side elevation;

Figure 2 is a central vertical section through the brake, on the line 22 of Figure 1;

Figure 3 is a partial section through the brakeapplying means andthrough the brake anchorage;

Figure 4 is a partial section through the adinstable floating shoeconnection, on the line 4--4 of Figure '1;

Figure 5 is a partial section on the line 5--5 of Figure l, showing oneof the steady rests;

Figure is a partial section on the line 6-6 of Figure l, showing thenovel shoe-positioning stop;

Figure 'l is a partial section on the line '1 -'l of Figure l. showinganother steady rest; and

Fig. 8 is a section through a modified form of brake anchor.

The illustrated brake. includes a rotatable drum- 10 at the open side ofwhich is' a support such as a backing plate 12, and within which isarranged the friction means of the brake. This friction means preferablyincludes a pair of novel interchangeable shoes 14 and 16 havingtransverse pivots 18 and 19 at their lower ends threaded to receive aright-and-left threaded rotatably-adjustable connection 20 having acentral collar formed with radial openings to receive a tool such as anail inserted through an opening 22 in the backing plate.

0n the side opposite the backing plate there is a retainer such as astamping 24, forked at its opposite ends to straddle a groove at the endof the right-hand'plvot 18 and behind a U-shaped washer 26 seated in agroove in the end of the left-hand pivot 19. Stamping 24 has lugs 28turned out at right angles toembrace the collar on connection 20, and ispunched to form a pro jection 30 serving as a. pawl yieldinglyinterlocking with the radial tool openings in the collar of connection20.

The backing plate 12 may be provided with rigidly-mounted steady restpins 32 engaging the sides of the shoe webs. These pins are preferablypositioned at or near a point 90 degrees remote from the brake applyingcam giving, with the pin 18 and cam, a good three point support for eachiioating shoe. A steady rest 34 may also be provided, which passesthrough an opening in shoe 14 and is provided at its end with a washerengaging the drum side of the shoe web and held by means such as aU-shaped Washer 36 snapped into a groove in the end of the rest.

Shoe 16 is provided with a novel eccentric stop 38, adjustably mountedin the backing plate and operable from outside the backing plate andhaving a stamped roller 40 engaging the inner face of the shoe rim. Thisroller is preferably retained in position by a plain washer 41 seated ona rabbeted portion in the shank of the stop, which washer is retained bya sheer riveted portion 43 of said shank. This stop may have aconcentric steady rest portion 42 projecting through an opening in theshoe web, and having at its end a washer engaging the drum side of theshoe web and held by means such as one of the U-shaped snap Washers 36.

Shoe 16 is urged against the adjustable stop roller 40, when the brakeis released, by means such as a novel auxiliary spring 44 inclined atsuch an angle as to act through the connection 20 to urge shoe 16 awayfrom the drum.

'I'he angle of spring 44 is preferably such as to urge both shoes 14 and16 bodily toward the upperA side of the drum, against novel anchorpivots 46 and 48 passing through elongated anchor openings 50 in theends of the shoes. Anchors 46 and 48 are grooved adjacent their ends toform end flanges and collars 52 between which the shoe webs areembraced. The plain and U washer construction disclosed in Figure 7-may, however, be substituted in lieu of the integral end flange asillustrated in Figure 8 wherein the anchor 146 has a collar 152-and hasat its end a plain washer held by a U-shaped washer 136. The largerportions of openings 50, nearest the ends of the shoes, are large enoughto pass over the end flanges of anchors 46 and 48, whereas the narrowerportions of these openings, which are held against the anchors when thebrake is released by means such as a main return spring 54 tensionedbetween the shoes, are too small for the passage of the end flanges ofthe anchors. The inner edges of openings 50, which are held against theanchors by spring 44, extend substantially parallel to the direction ofbrake-applying movement of the shoe ends andare preferably approximately15 degrees with the horizontal.

According to an important feature of the invention, the ends of theshoes or their equivalents are rounded on arcs having their centersadjacent the anchor ends of openings 50, i. e. substantially in thecenters of the anchors 46 and 48 when the brake is released, forengagement with thrust members such as square blocks 56 pivotallymounted between stampings 58 forming a floating applying lever connectedat its lower end by a pivot 60 to an arm 62 pressed on the attened endof a shaft 64. Shaft 64 terminates opposite the upper end of lever 58and arm 62 extends downwardly beside and parallel to the lever 58, boththe lever and arm extending at a sufficient angle to the vertical topermit efficient brake application with movement of the service pedal.

Shaft 64 is journaled in a bearing 68 fitting lin an enlarged opening inthe backing plate and rigidly secured to a reinforcing plate 70 restingat against the outer face of the backing plate and having at its endsspaced openings alined with openings in the backing plate. On the innerside of the backing plate there is another reinforcing plate 72, restingagainst the inner face of the backing plate and having an openingsleeved on the shaft bearing 68. Anchor pivots 46 and 48 are pressedinto openings in the ends of plate 72, to form studs projecting throughthe alined spaced openings in the backing plate and in plate 70 andreceiving nuts 74 co-operating with collars 52 to clamp the tworeinforcing plates 70 and 72 and the backing plate 12 together. Platev70 with its integrally secured bearing 68 together constitute asub-assembly unit, as does the plate 72 together with the anchor pins 46and 48 pressed therein. The openings in the backing plate are preferablyvertically elongated, permitting, with the enlarged opening for thebearing 68, a vertical adjustment of the two brake operatingsub-assembly units upon initial installation thereof.

It will be seen that blocks 56 thrust radially against the rounded endsof shoes 14 and 16, on lines passing through the centers of the anchorpivots, so that there is no tendency to shift the shoes on the anchors.Also the thrust on shoe 14 is some two times greater than the thrust onshoe 16. shoe 14 being the primary shoe which acts as a servo shoe whenthe car is moving forward and shoe 16 being the secondary shoe whichremains anchored when the car is moving forward. Thus the greater thruston shoe 14 acts 110 through spring 48 to hold shoe 16 against its anchor48 while shoe 14 is being forced against the drum in the preliminarystate of applying the brake.

As soon as shoe 14 engages the drum, it is urged 115 by the drumfriction in a counter-clockwise direction (if the car is moving forward)to apply shoe 16, which thus never leaves its anchorage during thenormal operation of the brake. If the car is. moving backward, shoe 14is urged clockwise 120 by the drum friction, to shift the anchorage topivot 46, so that the shift takes place before the brake is fullyapplied. Moreover during the shifting the lower edge of opening 50 inshoe 14 rubs against anchor 46, thus retarding the shifting movement. Asthe shifting thus takes place relatively slowly and not under load,there is no shock or noise.

While one illustrative embodiment has been described in detail, it isnot my intention to limit the scope of the invention to that particularembodiment, or otherwise than by the terms of the appended claims. Theadjustable connection between the shoes and the arrangement and mountingof roller 40 or its equivalent are re- 13:. spectively claimed in mydivisional applications Nos. 687,430 and 687,431, both filed August 30,1933.

I claim:

1. A brake comprising, in combination, a friction device adapted toanchor adjacent either of its ends and having at each of said ends arigid web with its end rounded in an arc lhaving its centerapproximately at the corresponding anchorage point and applying meansthrusting against said rounded ends.

2. A brake comprising, in combination, a friction device adapted toanchor adjacent either of its ends and having at each of said ends arigid web with its end rounded in an arc having its center approximatelyat the corresponding anchorage point and a floating applying devicehaving portions thrusting radially against said rounded ends.

3. A brake shoe having adjacent its end an anchor opening, and havingits end rounded on an arc having its center approximately at the anchorend of said opening.

4. A brake shoe having adjacent its end an elongated anchor opening, andhaving its end rounded on an arc having its center adjacent the end ofsaid opening furthest from the end of the shoe.

5. A brake shoe having adjacent one end an elongated opening with arelatively wide portion nearest the shoe end and a narrower portionfurther from the shoe end, in combination with an anchor pivot having aretaining part over which the relatively wide portion of the opening canpass but too large to permit the passage of said narrower portion.

6. A4 brake shoe having adjacent one end an elongated opening with arelatively wide portion nearest the shoe end and a narrower portionfurther from the shoe end. and having its end rounded on an are with itscenter in said narrower portion of the opening.

"I. A brake shoe having adjacent its end an anchor opening, and havingits end rounded on an arc having its center approximately at the anchorend of said opening, in combination with an applying device thrustingagainst the shoe radially of said arc.

8. A brake shoe having adjacent one end an elongated opening with arelatively wide portion nearest the shoe end and a narrower portionfurther from the shoe end, and having its end rounded on an arc with itscenter in said narrower portion of the opening, in combination with anapplying device thrusting against the shoe radially of said are.

9. A` brake backing plate having reinforcing parts provided with abearing for an operating shaft, in combination with a pair of anchormembers on opposite sides of the bearing and securing the parts to thebacking plate.

10. A brake backing plate having reinforcing parts provided with abearing for an operating shaft, in combination with a pair of anchormembers extending through the backing plate on opposite sides of thebearing and having collars on the inner side of the plate and nutsthreaded on their ends and co-operating with the collars to clamp saidparts to the backing plate.

11. A brake backing plate having a pair of spaced openings and a bearingopening between the spaced openings, in combination with a reinforcingmember lying flat against the outer face oi the pla-te and provided witha shaft bearing rigidly mounted at its center and fitting within thebearing opening of the plate and having spaced openings alined 'withthose in the plate, and another reinforcing member lying nat against theinner face of the plate and having a central opening fitting over saidbearing, and having rigidly mounted at its ends studs projecting throughthe alined spaced openings in the plate and the first reinforcing memberand securingthe two reinforcing members and the plate together.

12. vA lbrake backing plate having a pair of spaced openings and abearing opening between the spaced openings, in combination with areinforcing member lying flat against the outer face of the plate andprovided with a shaft bearing rigidly mounted at its center and fittingwithin the bearing opening of the plate and having Vspaced openingsalined with those in the plate,

`ings embracing said pivots and having ends formed on arcs with theircenters substantially at the axes of said pivots when the brake isreleased, and applying means thrusting radially of said arcs againstsaid ends.

14. A brake comprising, in combination, a drum, a pair of anchor pivotsat one side of the druxn, floating friction means having elongatedopenings embracing said pivots and having ends formed on arcs with theircenters substantially at the axes of said pivots when the brake isreleased, applying means thrusting radially of said arcs against saidends and acting with greater force on one of said ends than on theother, and a return spring connecting said ends and holding said otherend yieldingly anchored while said one end is forced against the drum,until the drum friction acting on saidfriction means determines theanchorage of the brake.

15. A brake -.comprising, in combination, a drum. a pair of anchorpivots at one side of the drum, floating friction means having elongatedopenings embracing said pivots and having ends formed on arcs with theircenters substantially at the axes of said pivots when the brake isreleased, and applying means thrusting radially of said arcs againstsaid ends, the inner sides of said openings being approximately parallelto the direction of brake-applying movement of said ends.

16. A brake comprisings, in combination, a

drum, a pair of anchor pivots at one side of the drum. floating frictionmeans having elongated openings embracing said pivots and having endsformed on arcs with their centers substantially at the axes of saidpivots when the brake is released, applying means thrusting radially ofsaid arcs against said ends, the inner sides of said openings beingapproximately parallel to the direction of brake-applying movement ofsaid ends, togetherwith an auxiliary spring urging said inner sides ofthe openings against the anchor pivots.

17. A brake comprising a backing plate. connected floating shoes on saidplate, anchorage means for the unconnected ends of said shoes, and aspring (44) connected at its ends respec tively to one shoe and to saidplate and nearly paralleling a line joining the ends of said shoe andurging it toward the anchorage means.

18. A brake comprising a backing plate, connected floating shoes on saidplate, anchorage means for the unconnected ends of said shoes, aretracting spring tensioned betweenvsaid shoes4 adjacent the anchoragemeans, and a spring (44) connected at its ends respectively to one shoeand to said plate and nearly paralleling a line joining the ends of saidshoe and urging it toward the anchorage means.

19. A brake comprising a backing plate, connected oating shoes on saidplate, anchorage means for the unconnected ends of said shoes, aretracting spring tensioned between said shoes 150 connected at its endsrespectively to one shoe and to said plate and substantially parallelinga line joining the ends of said shoe and urging it toward the anchoragemeans, and an applying device including a floating lever having spacedthrust parts engaging said unconnected ends respectively.

20. A brake comprising a backing plate, connected oating arcuate shoeson said plate, anchorage means for the unconnected ends of said shoes,and a spring connected at its ends respectively to one shoe only and tosaid plate and arranged in chordal relation to the central portion ofsaid shoe for urging it toward the anchorage means.

LUDGER E. LA BRIE.

